“One of the main ways Facebook gathered data in its early days was by encouraging new users to share their contacts with the platform. This resulted in many people having their phone numbers and email addresses shared with the tech giant, even if they never signed up to use Facebook or its other services.”
If you click right here, the good folks at Reclaim the Net will walk you through deleting your contact info from Meta.
I only had an assbook account to follow a penpal in Australia -- deleted that account -- and then to access a thyroid patients page -- deleted that account. But I got rid of the damn contact info when my email provider ended and I had to create new email accounts, which assbook does not have. No more emails begging for money, hurrah! No more "Wouldn't you like to be friends with someone you've never heard of and have nothing in common with?"
I think, not checking if they have data is better. If you check, you make sure they have it. If you don't, they might not have it. Schroedinger style.